The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Honing is generally defined as an abrasive machining process that produces a precision surface on a metal workpiece. It is most generally utilized to provide a smooth, dimensionally accurate finish on internal cylindrical surfaces such as the cylinder walls of internal combustion engines. This is achieved by moving one or more abrasive stones or hones on or over the surface of the workpiece, typically by simultaneously rotating the hones and translating (oscillating) them axially.
While the process is related to and often compared to grinding, the basic nature of the process renders it most suitable for precision final treatment of metal workpieces such as, as noted above, cylinders and similar bores. This precision is the result of the simultaneous rotation and axial oscillation of the hones which come in contact with a large area of the workpiece thereby averaging out both the imperfections of the hones and the bore. This averaging effect occurs in all honing processes and contributes to the accuracy and smooth finish of honed surfaces, especially bores.
Conventional hones and honing apparatus experience a common difficulty and that is controlling or limiting the dimensional increase in bore diameter during honing. That is, most honing machines utilized in machine shops rotate and axially oscillate the hones while the adjustable radial force applied to the hones is controlled by a foot pedal. Thus, although metal removal by honing is relatively slow compared to grinding, most machines depend upon the skill of the operator to efficiently and accurately control or limit the dimensional increase of a workpiece by honing. Obviously, overhoning a workpiece with the result that the completed bore, though smooth, is oversized is not only undesirable but may result in scrapping the workpiece. As explained above, however, although conventional hones are capable of providing extremely smooth inner cylindrical surfaces, dimensional control can be difficult due to the uncontrolled spring bias of the honing tool stones, i.e., the hones will continue to enlarge an opening as long as the tool is used.
An additional problem of honing is maintaining true and accurate on-center honing, especially if the axial length of the bore is relatively short. While this is less a problem in large, dedicated honing machines, maintaining true, on center honing with portable or hand held equipment can be difficult in the best of circumstances.
From the foregoing, it is apparent that improvements in both honing equipment and processes are both desirable and possible.